Miscanthus, also known as elephant grass, is a fast-growing source of biomass fuel Credit: Drax Utilities are looking for the holy grail: reliable baseload electricity derived from a sustainable, low carbon source and available around the clock, whatever the weather. Biomass, despite the rapid growth in its use, is still not ticking all of these boxes. It has also recently received bad press from environmental and scientific agencies as they question whether it reduces greenhouse gas emissions compared with fossil fuels. In November 2012, the UK's Royal Society for the Protection of Birds (RSPB), Friends of the Earth and Greenpeace called on the UK government to cancel plans to subsidise the burning of trees in coal power stations. The RSPB report 'Dirtier Than Coal?' says that generating power from typical conifer trees results in 49 per cent more emissions than burning coal, and calls on the government to withdraw public subsidy for generating from feedstock derived from tree trunks. Binding climate change targets and government support for low-carbon energy are bringing about widespread use of biomass in electricity. Coal power stations are co-firing biomass, and dedicated biomass facilities are springing up. As the sector develops, so does understanding of the impact of the large-scale use of fuel made from recently living plant material. It is increasingly clear that the diverse forms of biomass come with different life-cycle carbon emissions and varying green credentials.Initial national policies were based on the assumption that biomass energy is carbon neutral. Biomass has been included in energy portfolios as an infinitely renewable energy source like wind and solar, so it has been eligible for the same support. But closer study of the net greenhouse gas benefits of burning biomass shows that a more complex model of carbon accounting is required. This should include factors relating to the type, source and treatment of the biomass, modelling of forest growth, transport of the biomass and timing of emissions and sequestration.
Carbon Neutral or a Trojan Horse?